Fat-liquoring compositions

ABSTRACT

A fat-liquoring compositions for animal skins and leather containing as the active substance a content of an olefin sulfonation product produced by reacting an unbranched olefin or an olefin with a branched alkyl chain attached to one of the carbon atoms of the double bond with a strong sulfonating agent and then neutralizing and partially or completely hydrolyzing the sulfonated product with an aqueous solution of at least one member of the group consisting of alkali metal hydroxides, ammonia, alkyl amines and hydroxyalkyl amine, a method of fatliquoring leather and skins and fat-liquored leather and skins produced by the said method.

United States Patent [191 Plapper et al.

[ Oct. 16, 1973 FAT-LIQUORING COMPOSITIONS [75] Inventors: Jurgen Plapper,

Dusseldorf-Holthausen; Werner Stein, Erkrath-Unterbach Rhineland; Horst Baumann, Hilden Rhineland, all of Germany [73] Assignee: Henkel & Cie Gmbl-I,

Dusseldorf-Holthousen, Germany 22 Filed: on. 7, 1970 [2]] Appl. No.: 78,964

[52] US. Cl 8/9421, 8/9423, 8/9422, 252/857 [51] Int. Cl. Cl4c 5/00, C14c 9/02 [58] Field of Search 8/94.23 94.33, 94.2, 8/9422; 252/857 [56] References Cited UNITED STATES PATENTS 2,176,434 10/1937 Niedencom 8/9423 2,827,432 3/1958 2,353,752 8/1945 2,892,673 6/1959 Heyden et al 8/9423 OTHER PUBLICATIONS Schwartz et al., Surface Active Agents and Detergents, Vol. II, 1958 pp. 664-665.

Primary Examiner-Norman G. Torchin Assistant Examiner-J. P. Brammer Attorney-Hammond and Littell [5 7] ABSTRACT A fat-liquoring compositions for animal skins and leather containing as the active substance a content of an olefin sulfonation product produced by'reacting an unbranched olefin or an olefin with a branched alkyl chain attached to one of the carbon atoms of the double bond with a strong sulfonating agent and then neutralizing and partially or completely hydrolyzing-the sulfonated product with an aqueous solution of at least one member of the group consisting of alkali metal hydroxides, ammonia, alkyl amines and hydroxyalkyl amine, a method of fat-liquoring leather and skins and fat-liquored leather and skins produced by the said method. I

6 Claims, No Drawings FAT-LIQUORING COMPOSITIONS STATE OF THE ART Sulfonated vegetable or synthetically prepared fats, and oils are known as leather fat-liquoring substances. Preferred among these are mixtures of sulfonated and unsulfonated esters, chiefly of unsaturated fatty acids with mono-or poly-hydric alcohols of varying chain lengths, partly in conjunction with free fatty acids and soaps. In the usual fat-liquoring compositions the sulfonated fraction is generally between 20 and 40 percent by weight of the total amount of fatty substance used. An increase of the sulfonated fraction generally leads to a hard and dry hand of the leather treated therewith. Since the binding of the fat to the leather fibers increases with an increasing degree of sulfonation, it is desirable to increase the sulfonated fraction as much as possible in order to attain thereby a maximum resistance to water and solvents without having to make allowances for the disadvantages above.

OBJECTS OF THE INVENTION It is an object of the invention to provide novel fat liquoring compositions and agents for leathers and skins which do not suffer the disadvantages of the known fat-liquoring compositions.

It is another object of the invention to provide a novel fat-liquoring method for leather and skins and to the improved fat-liquored skins and leather produced thereby.

These and other objects and advantages of the invention will become obvious from the following detailed description.

THE INVENTION The novel fat-liquoring compositions of the invention contain as the active ingredient a content of an olefin sulfonation product produced by reacting an unbranched olefin or an olefin with a branched alkyl chain attached to one of the carbon atoms of the double bond with a strong sulfonating agent and then neutralizing and partially or completely hydrolyzing the sulfonated product with an aqueous solution of at least one member of the group consisting of alkali metal hydroxides, ammonia, alkyl amines and hydroxyalkyl amine.

Such olefin sulfonation products, especially when the degree of sulfonation is at least 50 percent, preferably 75 to 100 percent, are surprisinglymarked by a very high affinity for leather fibers and by excellent leather fat-liquoring properties. Very soft and pliable leathers with a plump hand can be obtained, which have a solvent-resistant binding of fatty substance of the order of 70 percent or more, depending on the degree of sulfonation. This increases further with a rising degree of sulfonation, without appreciably impairing the behavior of the leather fat-liquored therewith to water, especially when the olefin sulfonates contain longer chain lengths.

Suitable starting substances for the preparation of the olefin sulfonation products include unbranched monoolefins or mono-olefins with a branched alkyl group attached to a carbon atom of the double bond and of chain lengths of C to C Unbranched olefins of 14 to 22 carbon atoms with a terminal double bond, and branched-chain olefins of 16 to 24 carbon atoms which contain one to 12 carbon atoms in the branched alkyl chains, are preferred. Such olefins are prepared, for example, by cracking of parafins, ethylene polymerization, dehydrohalogenation of monochloroparafins and other well known technical processes. The olefins may be used in the commercially obtainable qualities, preferably as mixtures of compounds of different chain lengths, while the content of saturated parafins and diolefins may amount up to 10 percent by weight of the mixture.

Known strong sulfonation agents, especially gaseous or liquid sulfur trioxide or chlorosulfonic acid, are suitable for carrying out the sulfonation reaction. These may in some cases be used in the presence of gaseous diluents such as nitrogen, carbon dioxide or sulfur dioxide, or liquid solvents. The sulfonation is preferably effected with a mixture of sulfur trioxide and air without the use of a solvent. The S0 concentration amounts to 0.5 to 10 percent by volume, preferably 2 to 6 percent by volume. In order to obtain favorable leather properties, the olefins are reacted with at least 0.5 mol., preferably 0.75 to 1.3 mol of the sulfonating' agent.

The reaction is effected by intensively admixing the gaseous mixture containing sulfur trioxide with the liquid olefins in a suitable reaction apparatus at temperatures usually between 0 and C. The reaction times amount to less than 1 second up to 2 hours, depending upon the apparatus used for the reaction. Suitable sulfonation reactors include those which operate on the annular gap, thin layer, falling film or atomization principle.

The sulfonation may be carried out discontinuously or continuously. Light-colored products which are especially suitable for the invention, are obtained principally by a continuous operation in the abovementioned apparatus, which may be operated in one state or in several stages by the cascade principle. It is important in all cases for the contact time between the olefin and the sulfur trioxide-containing gas mixture to be short and for care to be taken to remove the heat of reaction efficiently, since otherwise dark colored products are formed.

Sulfonation processes of the type described, as well as the apparatus appropriate for the reaction, are described, for example, in the DAS No.. 1,215,695 and DAS No. 1,270,549 and also in the DOS No. 1,468,013.

In the sulfonation using gaseous sulfur trioxide, mixtures of various sulfonic acids and alkanesultones are formed. Therefore, for the preparation of water soluble products, not only is a neutralization with aqueous alkali needed, but also an acid or alkaline hydrolysis of the sultone fractions is required, in which case hydroxyalkane sulfonates are principally obtained. If it is desired to obtain sultone-containing products, however, this hydrolysis can be wholly or partly omitted. Products can be prepared depending upon the method and degree of hydrolysis which consist of alkenesulfonates, varying amounts of sultones and possibly hydroxyalkane sulfonates, as well as disulfonates which may likewise contain hydroxyl groups. All of the said types of active substances are present as isomeric mixtures with regard to the position of the sulfonate group or groups, the hydroxyl groups and the double bond. The relative amounts of hydroxyalkane sulfonate, alkenesulfonate and disulfonate depend to a certain extent on the conditions of the sulfonation and hydrolysis. The reaction conditions in the hydrolysis especially influence the relative amounts of hydroxyalkane-and alkene-sulfonates. As the excess of alkaline solution increases during the hydrolysis and as the hydrolysis temperature rises (50 to 200C preferably 80 to 180C.) the amount of hydroxyalkane sulfonates is decreased in favor of the alkenesulfonates.

The sulfonated olefins are neutralized with aqueous solutions of alkali metal hydroxides, such as sodium or potassium hydroxides, ammonia or alkyl amines or hydroxyalkylamines at temperatures from 20 to 60C, and are then hydrolyzed with further alkali solution depending upon the degree of hydrolysis desired. The neutralization and also the hydrolysis may be carried out discontinuously or continuously. The hydrolysis is effected at 50 to 200C, with temperatures over 100C requiring the use of a pressure apparatus. The time of hydrolysis will vary according to the temperature used, between 6 hours at 80C and minutes at 200C. Preferably the reaction is carried out at 100C. for 2 to 4 hours or at 160 to 180C for 10 to minutes.

The water content of the end products is determined by the concentration of the aqueous base used for the neutralization and hydrolysis. The olefin sulfonation products usually have a content of 45 to 70 percent by weight of active substance. More highly concentrated products are only homogenized with difficulty and due to their, for example, high viscosity or solid consistency, are hard to process further. A homogenization of pasty products, for example, can be done in a heatable kneader. With regard to processability and properties for technical application, sulfonation products based on unbranched a-olefins of chain lengths C to C in the form of their ammonium salts have proved especially favorable.

When in special cases the color of the olefin sulfonation products obtained is not light enough, bleaching with sodium hypochlorite or hydrogen peroxide in neutral aqueous solution can be effected. The bleaching time may be about 2 or 3 hours at temperatures from 40 to 60C. A description of such a process is found in DAS No. 1,185,178.

The sulfonation products when used as leather fatliquoring substances, demonstrate good liquor consumption, high adhesion to the leather fibers and low solvent extractability, and also favorable water behavior. The treated leather has a light color.

The products may be used alone or in admixture with further customary leather treatment substances such as sulfonated or unsulfonated oils or fats or synthetic fatliquoring substances, such as chlorinated parafiins and paraffin sulfonates or mineral oils. By this, both the binding of the fat and the fat-liquoring effect can be favorably influenced. The fat mixtures preferably contain about 10 to 50 percent by weight of the products of the invention based on the total amount of the leather fatliquoring composition.

The novel method of the invention of'fat-liquoring leather and skins comprises treating leather or skins with a fat-liquoring composition in the form of an aqueous solution or emulsion having 1 to 10 percent by weight of the active ingredient which is at least one of the novel olefin sulfonation products discussed above, based on the total fat-liquoring bath.

The products are well absorbed by the leather and give excellent softening and fat-liquoring effects which possess a remarkable resistance towards water and aqueous or organic cleaning agent solutions. Their tendency to migrate in case of thermal stress is very small, so that for example, bonding processes or the vulcanization of rubber soles on to shoe uppers can be carried out without difficulty. The softness and pliability of the leather treated with the compositions of the invention is particularly desirable.

In the following examples there are described several preferred embodiments to illustrate the invention. However, it should be understood that the invention is not intended to be limited to the specific embodiments.

EXAMPLE 1A 726 g. (3 mol) of a C -C -a-olefin mixture (average number of carbon atoms 17.3, iodine value 109 were placed in a three-necked sulfonation flask of 2.5 liters capacity which was provided with a thermometer, a gas inlet pipe reaching substantially to the bottom of the flask, a gas exit pipe reaching substantially to the bottom of the flask, a gas exit pipe and a high-speed stirrer. The said mixture was sulfonated to 75 percent by blowing in a sulphur trioxide-air mixture which contained about 3 percent vol. of $0 with vigorous stirring. in the course of 1.5 hours, 181 g. (2.26 mol) of 80;, were passed therein and the temperature of the reaction mixture was kept at 20 to 30C by external cooling. At the end of the sulfonation, the liquid brown reaction product was treated with 960 g. of 10 percent (214 mol) sodium hydroxide solution and was then hydrolyzed by refluxing for 4 hours. The alkaline reacting hydrolyzate was neutralized with sulfuric acid and brought to a final concentration of 59 percent of active substance by evaporation and subsequent homogenization to obtain 1,665 g. of a yellow-brown pasty product.

EXAMPLE 1B Chrome-tanned and weakly after-tanned upper leather was fat-liquored for minutes with 5 percent by weight of the active substance of the Example 1A and 200 percent by weight of water at 60C and the leather was then dried and finished in the usual way to obtain a light-colored leather with a plump hand with about 15 percent of fractions extractable by solvents (based on total fat absorbed) which was very suitable for vulcaniz'able upper leather.

EXAMPLE 2A The sulfonation reaction of Example 1A was repeated and after sulfonation, the reaction product was treated with 820 g. of 5 percent (2.4 mol) aqueous ammonium hydroxide and was then hydrolyzed by refluxing for 4 hours. The hydrolyzate was neutralized and then brought to a final concentration of 61 percent of active substance by evaporation and homogenization to obtain 1,590 g. of a yellow-brown, homogeneous, pasty product.

EXAMPLE 2B owing to its relatively small extractable and migratable fat fractions, was suitable for the vulcanization and bonding in the later processes in the leather manufacture.

EXAMPLE 3A In the sulfonation apparatus described in Example 1A, 484 g. (2 mol) of a C -C a-olefin mixture were reacted with 182 g. (2.27 mol) of 80;, by blowing in an SO -air mixture containing about 3 percent by vol. of SO; in the course of 1.5 hours at temperatures from 20 to 40C (degree of reaction 95 percent). After the end of the sulfonation, the liquid brown reaction product was treated with 800g. (2.35 mol) of 5 percent aqueous ammonium hydroxide and then hydrolyzed by heating for 15 minutes at 170C. in an autoclave. The hydrolyzate was neutralized and brought to a final concentration of 63 percent active substance by evaporation and then homogenization to obtain 1,095 g. of a yellowbrown pasty product.

EXAMPLE 3B extractability of 15 to 20 percent, was useful especially for the manufacture of clothing leather fast to chemical cleaning.

EXAMPLE 4A In the sulfonation apparatus of Example 1A, 726 g. (3 mol) of a C -C a-olefin mixture were reacted in the course of 1 hour at temperatures from 20 to 30C. with 122 g. (1.53 mol) of 80;, by blowing in a S -air mixture containing about 3 percent vol. of S0 (degree of reaction 50 percent). After the sulfonation, the liquid brown reaction product was treated with 800 g. of (1.6 mol) 8 percent sodium hydroxide and then hydrolyzed by refluxing for 4 hours. The hydrolyzate was neutralized with sulfuric acid and brought to a final concentration of 62 percent by evaporation and then homogenization to obtain 1,450 g. of a yellowish pasty product.

EXAMPLE 4B A chrome-tanned glove leather of sheepor kid-skin was fat-liquored for 45 minutes with 6 percent by weight of active substance of the fat-liquoring composition of Example 4A and 200 percent by weight of water at 60C., egged, dyed and again fat-liquored in the usual way with 2 percent by weight of the same substance, and subsequently finished as usual to obtain a soft, elastic, pliable glove leather which due to the low fat-extractability of about 30 percent (based on total fat content) was specially resistant to washing and cleaning.

EXAMPLE A In the sulfonation apparatus of Example 1A, 452 g. (2 mol) of a C -C a-olefin mixture (average number of carbon atoms 16.2; iodine value 119) were reacted with 182 g. (2.27 mol) of S0 in the course of 1.5 hours at temperatures from 20 to 40C., by blowing in a $0 air mixture containing about 3 percent by vol. of (degree of reaction 96 percent). After sulfonation, the liquid brown reaction product was treated with 800 g. of 5 percent aqueous ammonium hydroxide (2.35 mol) and then was hydrolyzed by refluxing for 4 hours. The hydrolyzate was neutralized and brought to a final concentration of 58 percent of active substance by evaporation and subsequent homogenization to obtain 1,155 g of a yellow-brown pasty product.

EXAMPLE 5B Chrome-tanned hose leather for technical pumps was fat-liquored for 45 minutes with 5 percent by weight of active substance of the product of Example 5A and 200 percent by weight of water at 60C and was dried and finished in the usual way to obtain a specially resistant hose leather with a long life due to the low fat-extractability of about 15 percent compared with heat and degreasing substances.

EXAMPLE 6A The sulfonation reaction of Example 3A was repeated and after the end of the sulfonation, the-reaction product was cautiously neutralized with 740 g. (1.3 mol) of 7 percent aqueous sodium hydroxide at a temperature of 30C to 50C with cooling to obtain 1,360 g. of a yellow-brown pasty product, which contained 50 percent of active substance (14 percent thereof being sultone). The sultone fraction in the product was found by determination of the saponification value in a petroleum ether extract and the total content of active substance was determined by an alcohol extract as in the other examples.

EXAMPLE 6B The reaction product of Example 6A was used for the fat-liquoring of upper leather by the procedure of Example 28 to obtain a light-colored, soft, pliable upper leather with a fat adhesion of about percent, which can be denoted as specially fast to solvents.

EXAMPLE 7A EXAMPLE 7B The substance of Example 7A was used for the manu facture of suede clothing leather by the procedure of Example 3B to obtain a good washable leather resistant to dry cleaning and which had a solvent extractability of about 20 percent with exhaustive, extraction.

EXAMPLE 8A In the sulfonation apparatus described in Example 1A, 560 g. (2 mol) of 2-octyldodecene-l (iodine value ,96), which still contained small quantities of 9-methy1- nonadecene-8 and other C olef'ms, were reacted with 176 g. (2.2 mol) of $0 in the course of 1.5 hours at temperatures from 20 to 45C by blowing in a SO -air mixture containing about 3 percent vol. of 80;; (degree of reaction 94 percent). After the end of the sulfonation, the liquid brown reaction product was treated with 840 g. (2.46 mol) of percent aqueous ammonium hydroxide and then was hydrolyzed by refluxing for 4 hours. The hydrolyzate was neutralized and brought to a final concentration of 57 percent of active substance by evaporation and then homogenization to obtain 1,330 g. of a yellow liquid product.

EXAMPLE 8B The above reaction product was used to fat-liquor chrome-tanned and weakly after-tanned upper leather for 45 minutes with 5 percent by weight of active substance of a mixture of 50' parts by weight of the reaction product of Example 8A, 40 parts by weight of sulfonated sperm oil and parts by weight of wool fatand 200 percent byweight of water at 60C to obtain a soft, pliable upper leather with a plump hand which in spite of the co-use of natural fats, had a relatively small fat-extractability of about 50 percent.

EXAMPLE 9A In the sulfonation apparatus of Example 1A, 526 g. (1.5 mol) of a C -C a-olefin mixture (average number of carbon atoms 25), which consisted of about 60 percent of olefins with terminal double bonds and about 40 percent with non-terminal double bonds, were reacted with 84 g. (1.05 mol) of SO; in the course of 1.5 hours at temperatures from 60 to 70C by blowing in a SO -air mixture containing about 3 percent vol. of 50 (degree of reaction 70 percent.) After sulfonation, the viscous brown reaction product was treated with 630 g. (1.1 mol) of 7 percent aqueous sodium hydroxide and then was hydrolyzed by heating at 160C for 20 minutes in an autoclave. The hydrolyzate was neutralized with sulfuric acid and brought to.a final concentration of 55 percent active substance by evaporation and homogenization to obtain 1,170 g. of a brown solid product.

EXAMPLE 9B A chrome-tanned and weakly after-tanned upper leather was fat-liquored for 45 minutes with 5 percent of active substance of a mixture of 40 parts by weight of the reaction product of Example 9A and 60 parts by weight of the product of Example 3A and 200 percent of water at 60C, and was finished in the usual to obtain an elastic upper leather with a plump hand of which about percent of the fat content was bound fast and which had a specially favorable water behavior due to the fraction of long-chain olefin sulfonates.

Various modifications of the compositions and method of the invention may be made without departing from the spirit or scope thereof and it is to be understood that the invention is to be limited only as defined in the appended claims.

We claim:

1. A method of fat-liquoring leather and skins comprising contacting tanned leather or skins with an aqueous solution or suspension of l to 10 percent by weight of a fat liquoring agent consisting of an-olefin sulfonation product produced by reacting a member selected from the group consisting of an unbranched olefin of 14 to 22 carbon atoms having a terminal double bond and an olefin with a total of 16 to 24 carbon atoms and -which includes a branched alkyl chain of l to 12 carbon atoms attached to one of the carbon atoms of the double bond with a strong sulfonating agent to a sulfonation degree of at least 50 percent and then neutralizing and partially or completely hydrolyzing the sult'onation product with an aqueous solution of at least one member of the group consisting of alkali metal hydroxide, ammonia, alkyl amines and hydroxyalkylamine.

2. The method of claim 1 wherein the strong sulfonating agent is an SO -air mixture.

3. The method of claim 1 wherein the concentration is 0.5 to 10 percent by volume in the SO -air mixture.

4. The method of claim 1 wherein the degree of sulfonation is 75 to percent.

5. The method of claim 1 wherein the neutralization and hydrolysis is effected with an aqueous solution of a member selected from the group consisting of sodium hydroxide and ammonia.

6. The method of claim 1 which also contains at least one member of the group consisting of sulfonated or unsulfon ated fats and oils, chlorinated parafins, sulfonated parafins and mineral oils. 

2. The method of claim 1 wherein the strong sulfonating agent is an SO3-air mixture.
 3. The method of claim 1 wherein the SO3 concentration is 0.5 to 10 percent by volume in the SO3-air mixture.
 4. The method of claim 1 wherein the degree of sulfonation is 75 to 100 percent.
 5. The method of claim 1 wherein the neutralization and hydrolysis is effected with an aqueous solution of a member selected from the group consisting of sodium hydroxide and ammonia.
 6. The method of claim 1 which also contains at least one member of the group consisting of sulfonated or unsulfonated fats and oils, chlorinated parafins, sulfonated parafins and mineral oils. 